1. Public Health School, Henan Medical College, Zhengzhou 451191, China
2. Institute for Chronic Disease Control, Henan Provincial Center for Disease Control and Prevention, Zhengzhou 450016, China
3. Anti-TB Institute, Henan Provincial Center for Disease Control and Prevention, Zhengzhou 450016, China
4. Dalla Lana School of Public Health, University of Toronto, Toronto, ON M5S 1A1, Canada